Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: De Sisti on 24 September, 2020, 10:46:29 am
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In trying to remove a shimano bottom bracket (for routine maintenance) I have rounded off the grooves
of the bottom bracket cup. Any ideas on how to successfully progress with the task?
I have used copious amounts of wd40 in the draining hole as part of the removal process prior to attempting the bb removal.
(https://live.staticflickr.com/31337/50378525392_8922e19f70_n.jpg)
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We appear to be looking at the non-drive side in the pic - and a normal tapered square-drive cartridge type? If so . . .
A solution I've used successfully is to use the crank bolt to bolt the removal tool to the axle (obviously on the drive side) - and as tight as you can get it into the splines (hopefully there are some bits left to grip!). You may need a couple of washers and depending on the removal tool a different one (this works with the Park Tool remover) - then with a big spanner try turning the tool to unscrew the cartridge. I hesitate to say it but I assume you are aware that the drive side is a LH thread . . . .
It also often helps, if you can, to loosen the non-drive side supporting cup as that sometimes grips the BB unit.
When you have the cartridge out, if the non-drive cup is plastic a bit of heat and some prodding with a screwdriver usually distorts the plastic enough to get it out.
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As mentioned above bolting a good tool to the cup dramatically reduces the chances of camming out and/or slipping. If you don't have the pedros tool or similar, then TL-UN74 (and others equally shallow) is about the easiest one to bolt to the BB spindle; you just need a big washer and the normal crank bolt.
(https://www.jensonusa.com/globalassets/product-images---all-assets/shimano/tl408b00.jpg)
most other BB tools are much deeper and need the pedros tool (or something equally special) to bolt them to the BB spindle.
cheers
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I'm a fan of Pedros Tool (https://pedros.com/products/tools/pedal-crank-and-bottom-bracket/bb-socket-holder-ii/), though lots of people seem happy with improvising. Mine is the simpler, previous version.
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As mentioned above bolting a good tool to the cup dramatically reduces the chances of camming out and/or slipping. If you don't have the pedros tool or similar, then TL-UN74 (and others equally shallow) is about the easiest one to bolt to the BB spindle; you just need a big washer and the normal crank bolt.
(https://www.jensonusa.com/globalassets/product-images---all-assets/shimano/tl408b00.jpg)
most other BB tools are much deeper and need the pedros tool (or something equally special) to bolt them to the BB spindle.
cheers
Ah - _ should have mentioned you might need a bolt longer than the crank bolt if the tool is deep (the Park is) - I can't remember offhand the size of the special bolt I have, all I remember is that it's a smaller pitch than you'd expect for the bolt size (Brucey will know !)
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I was always told to remove the cup on the non-drive side first.
I have one of the crank bolts (Park BBT-2) and have ordered the Pedros tool. Hard to visualise
how it will fit. Pictures anyone? Hope all goes well.
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I was always told to remove the cup on the non-drive side first.
Me too.
I have one of the crank bolts (Park BBT-2) and have ordered the Pedros tool. Hard to visualise
how it will fit. Pictures anyone? Hope all goes well.
It's pretty obvious when you get hold of it. Screw the tool fully home into the BB spindle in place of the crank bolt. Turn the ring on the tool down till it butts firmly against the BB fitting tool, holding it in place. The nearest I could find was this page for a similar tool (http://www.superbiketool.com/prod4.asp?menu=3&cid=2&pid=351), with some videos. That tool is more like the original Pedro; I'm not sure why they've added all the springs and things in the Mark II, but I don't think it changes the basic concept.
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Thanks Drossall, video makes sense now.
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Probably too late - but this is the bolt spec: M8 1.0mm FINE PITCH
https://www.ebay.co.uk/itm/M8-1-0mm-FINE-PITCH-BLACK-SOCKET-CAP-SCREWS-HIGH-TENSILE-12-9-ALLEN-KEY-BOLT/361363430123?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
This is the bolt I bought, used with a big washer on the Park Tool tool
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Remarkedly, the Pedros tool that I ordered yesterday arrived this afternoon (I didn't pay
for next day service). I managed to remove the bottom bracket. However, I had to do it
from the drive-side, as the Park tool kepton slipping and rounding off the grooves.
Will have a think about how to remove the non-drive side cup. Bottom bracket felt
very notchy, so will be replaced in due course.
(https://live.staticflickr.com/65535/50383069687_6db976b043_n.jpg)
(https://live.staticflickr.com/65535/50383070642_5bfd36a24d_w.jpg)
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That's a special paint job on that frame !
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Is that a titanium frame? If it were aluminium I would be inclined to suggest that lots of boiling water (as in 100°C) might be your friend but I don't know if it will work on Ti.
I am planning to do a couple of french bb cups for which I don't have a spanner by grinding two grooves across the diameter of the cup full thickness (but stopping before going into the thread) so that I can wedge a hefty piece of steel flat in to act as a spanner. Just need bil's great hefty bench vice to hold it and turn the frame. But I'm in no rush, it's not urgent!
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It is a titanium frame, and yes, light can be deceptive.
this (https://www.sheldonbrown.com/tooltips/bbcups.html)method looks interesting.
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The Sheldon bolt and nut method? That's what I'd try if the cup is damaged.
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I assume the non-drive cup is a metal not plastic one? If plastic then hacking with a sharp instrument hacksaw blade across the threads can usually get a split in it and then pull it out.
With metal cups I have some success with GENTLY filing a slot in the side/thread (inline/across the BB shell) and then with a small chisel-end drift (punch) gently tap the cup with the drift in the slot you've made - once it starts to move it will probably move very easily - again a reminder - it's a conventional RH thread so punch it anti-clockwise.
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The Sheldon bolt and nut method? That's what I'd try if the cup is damaged.
You would need two specifically sized washers, together with a nut and bolt, to do that as there's very little to grip on with the cup - the Sheldon method is for the old style cup and axle BBs where there's load of face on the cup to grip.
The large washers that usually bolt the headboards to beds are pretty much the right size? (Large flange and M8 bolt hole)
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It is a titanium frame, and yes, light can be deceptive.
this (https://www.sheldonbrown.com/tooltips/bbcups.html)method looks interesting.
Fitting anything, even bottle cage bolts, into titanium needs especial care. Firstly, titanium can “ gall” very easily
Secondly some metals can react with titanium over time I believe, so an appropriate fitting paste/grease is needed.
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Aluminium anti-seize was the stuff to use back when Ti was popular on MTBs for things like allen key skewers. Fills the threads and prevents galling. Copper anti-seize is almost as good.
https://www.ebay.co.uk/itm/303704484586
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i'd cut two-three grooves with a hacksaw blade and punch a section out, then remove the rest.
titanium, while doesn't rust, is prone to galling, so every interface needs some sort of treatment/barrier.
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i'd cut two-three grooves with a hacksaw blade and punch a section out, then remove the rest.
It took a bit of persuasion, but got there in the end. :thumbsup:
(https://live.staticflickr.com/65535/50394535647_1e16164ddc_w.jpg)
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Excellent - now make with the copper grease!
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Excellent - now make with the copper grease!
Back in 1994, the bloke who taught me bicycle maintenance advised me to get a tub of
copper grease. He said I'd still have half of it in 20 years time. He was spot on. There's
about half of it still left in the tub. I have used it liberally over the years. I think I may
have over-tourqued the bb and cup. Will make sure I use the torque wrench in future
and not rely on feel.
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i'd cut two-three grooves with a hacksaw blade and punch a section out, then remove the rest.
It took a bit of persuasion, but got there in the end. :thumbsup:
(https://live.staticflickr.com/65535/50394535647_1e16164ddc_w.jpg)
Huzzah !!
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Phew!
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Excellent - now make with the copper grease!
Back in 1994, the bloke who taught me bicycle maintenance advised me to get a tub of
copper grease. He said I'd still have half of it in 20 years time. He was spot on. There's
about half of it still left in the tub. I have used it liberally over the years. I think I may
have over-tourqued the bb and cup. Will make sure I use the torque wrench in future
and not rely on feel.
... been there but with a can of black Moly grease that's required for the front suspension gubbins on F-frame Moultons - bike has long gone (to Nuttycyclist formerly OTP - where did he get to?) but the grease is still in the shed, with 95% left.